Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2022	Sep. 30, 2021
Income Taxes [Line Items]
Gross unrecognized tax benefits	$ 13,423	$ 15,199
Unrecognized tax benefits that, if recognized, would affect the effective tax rate	8,588
Possible decrease in unrecognized tax benefits liability	$ 4,345
Domestic Tax Authority [Member]
Income Taxes [Line Items]
Year remaining open to tax examination	2018
State and Local Jurisdiction [Member]
Income Taxes [Line Items]
Year remaining open to tax examination	2017
Foreign Jurisdiction [Member]
Income Taxes [Line Items]
Year remaining open to tax examination	2017